Plugboard systems are generally used in conjunction with computers to facilitate the connecting and disconnecting of arrays of electrical terminals. These plugboard systems are generally comprised of a stationary rear bay of electrical terminals and a movable front bay of electrical terminals. The rear bay usually contains coaxial connectors, signal contacts and power contacts that are arranged in rows or columns and are connected to associated electronic circuits. These circuits can be interconnected by corresponding coaxial connector and contact patchcords selectively arranged in holes in the movable front bay. When the front bay is moved as a unit relative to the rear bay from an inoperative position to an operative connecting position, the coaxial connectors, signal contacts and power contacts in the front bay are electrically connected with respective coaxial connectors, signal contacts and power contacts in the rear bay.
Generally, the electrical terminals are the type that axially connect with each other, such as for example pins and sockets; thus the front bay must be moved straight toward and away from the rear bay during the connecting and disconnecting of the coaxial connectors, signal and power contacts. Electrical terminals for flat power cable, such as those described in U.S. Pat. No. 4,887,976, are also axially connected. The electrical terminals may be mounted in dielectric housings which are then mounted to the framework of the front and rear bays, thus defining modular arrangements facilitating programming and service and repair.
A large number of connectors is involved in these plugboard systems which results in substantial mechanical resistance when the connectors are connected and disconnected. An operating mechanism is therefore required that can effectively connect and disconnect the connectors and precisely guide the connectors into electrical engagement without damaging the connectors over repeated operations thereby assuring optimum electrical continuity between the interconnected bays.
Operating mechanisms are known for plugboard systems to connect and disconnect the electrical terminals of the front bay with respective electrical terminals of the rear bay. In one such system disclosed in U.S. Pat. No. 4,542,951, the operating mechanism comprises hanger plates and sliding cam plates mounted on opposite side members of a rear frame of the rear bay, and the cam plates have profiled cam slots and L-shaped slots therein. An operating member, including a shaft with an actuator lever arm at one end, is pivotally mounted into the rear frame and includes rollers which are disposed in the L-shaped slots. When the operating member is moved from one position to another position, the rollers move along the L-shaped slots causing the cam plates to move linearly vertically along the sides of the rear frame. This causes the cam slots to move linearly horizontally support members on a front frame thereby connecting or disconnecting the electrical terminals in a relative axial movement.
Electrical terminals are also known in which the electrical contacts of each of the terminals being connected are first moved axially to be side-by-side with each other with substantially little or no engagement when the connectors are moved together. Then, the contacts of the terminals are moved laterally against each other in a wiping action caused by a camming arrangement in one of the connectors to generate the preselected normal force between the respective contacts to establish assured electrical connection therebetween. Such arrangements are known as "zero-insertion force" or ZIF connectors, and the contacts are blade shaped cantilever beams at least one of which is slightly deflected by the other to a spring loaded mated position against the other upon camming. Such ZIF style contacts and their actuation is disclosed in U.S. Pat. No. 4,664,456 and also in AMP Technical Paper No. P261-82, "Design Considerations for High Pin Count Cammed Rectangular Zero Insertion Force Connectors" (1982).
One such ZIF connector is a CR ZIF connector system sold by AMP Incorporated, Harrisburg, Pennsylvania and described in AMP Instruction Sheet No. IS 6687 (1987). The connector is a cammed rectangular connector having either 520 or 1040 mating pairs of terminals. Within a first one of the plug and receptacle framework assemblies are disposed a plurality of dielectric housing modules each containing a plurality of contacts. The modules are fixedly mounted to a common subframe within a first framework assembly. Also disposed within the assembly is another housing containing conventional pin-and-socket contacts, the housing being fixedly mounted within the cover. The assembly includes a cam which when actuated moves the subframe and its fixedly mounted modules in the common lateral direction, but which does not move the fixedly mounted housing. The first framework assembly is axially mated with the mating second framework assembly, the modules upon being cammed urge the contacts secured therein against now adjacent mating contacts of the mating second assembly so that the contacts are deflected against spring bias to establish sufficient normal force against the connecting contacts.
Also sold by AMP Incorporated is a ZIF connector having one or a few housing modules containing male or female terminals requiring axial mating, and one or a few housing modules containing ZIF-style contacts requiring lateral mating after being moved side-by-side. This cammed rectangular system is described in AMP Instruction Sheet No. IS 7669 (1987). All of the housing modules are disposed within a pair of mating assembly covers: in the active cover the modules containing axial mating terminals are fixedly mounted, and the modules containing the ZIF-style terminals are float mounted; in the mating cover the mating connector modules are fixedly mounted. The active cover includes a cam which when manually actuated such as by rotation moves the float mounted housing modules in a common lateral direction. During mating of the assembles, the float mounted housing modules upon being cammed urge the ZIF-style terminals secured therein against adjacent contacts of the mating assembly so that the contacts are deflected against spring bias to establish sufficient normal force against the mating ZIF-style contacts.
Conventionally, separate plugboard systems have been used with separate operating mechanisms for each type of electrical connector and required movement, either axial or normal, but not both. These prior art operating mechanisms for plugboard systems do not presently and cannot be easily adapted to provide both axial movement to connect plugboard systems having pin and socket electrical terminals (such as power contacts, coaxial connectors, and signal contacts), and normal movement for "zero force connectors." While pin and socket and other types of electrical connectors need a substantial axial force to mate a front and rear bay having large numbers of electrical terminals, zero force connectors need a very precise normal movement to bias contacts of the mating assembly to a predetermined contact. Having separate mechanisms for each type of movement within one framework, however, is not fully satisfactory because one or more plugboard systems may need to be used within a very limited space. Also, this solution creates wiring harness complications, particularly if various types of electrical connectors need to be used.